PHP 4.4 and 5.1.6 are now the minimum PHP requirements, for brave souls
pear upgrade -f PEAR will allow people with lower versions
to upgrade to this release but no guarantees will be made that it will work properly.

Support for XML RPC channels has been dropped - The only ones that used it
(pear.php.net and pecl.php.net) have used the REST interface for years now.
SOAP support also removed as it was only proof of concept.